French submarine Surcouf

History
Surcouf circa 1935
France
Name:	Surcouf
Namesake:	Robert Surcouf
Ordered:	4 August 1926
Builder:	Arsenal de Cherbourg
Laid down:	1 October 1927
Launched:	18 October 1929
Commissioned:	3 May 1934
In service:	1934–1942
Refit:	1941
Struck:	6 December 1943
Identification:	Pennant number: N N 3
Honors and awards:	Resistance Medal with rosette
Fate:	Sunk, 18 February 1942
General characteristics
Type:	Cruiser submarine
Displacement:	3,250 long tons (3,300 t) (surfaced) 4,304 long tons (4,373 t) (submerged) 2,880 long tons (2,930 t) (dead)
Length:	110 m (361 ft)
Beam:	9 m (29 ft 6 in)
Draft:	7.25 m (23 ft 9 in)
Installed power:	7,600 hp (5,700 kW) (surfaced) 3,400 hp (2,500 kW) (submerged)
Propulsion:	2 × Sulzer diesel engines (surfaced) 2 × electric motors (submerged) 2 × screws
Speed:	18.5 knots (34.3 km/h; 21.3 mph) (surfaced) 10 kn (19 km/h; 12 mph) (submerged)
Range:	Surfaced: 18,500 km (10,000 nmi; 11,500 mi) at 10 kn (19 km/h; 12 mph) 12,600 km (6,800 nmi; 7,800 mi) at 13.5 kn (25.0 km/h; 15.5 mph) Submerged: 130 km (70 nmi; 81 mi) at 4.5 kn (8.3 km/h; 5.2 mph) 110 km (59 nmi; 68 mi) at 5 kn (9.3 km/h; 5.8 mph)
Endurance:	90 days
Test depth:	80 m (260 ft)
Boats & landing craft carried:	2 × motorboats in watertight deck well
Capacity:	280 long tons (280 t)
Complement:	8 officers and 110 men
Armament:	2 × 203 mm (8 in) guns (1 × 2) 2 × 37 mm (1.46 in) anti-aircraft guns (2 × 1) 4 × 13.2 mm (0.52 in) anti-aircraft machine guns (2 × 2) 6 × 550 mm (22 in) torpedo tubes (2 external) (14 torpedoes) 4 × 400 mm (16 in) torpedo tubes (4 external) (8 torpedoes)
Aircraft carried:	1 × Besson MB.411 floatplane
Aviation facilities:	Hangar

Seizure of Surcouf

Part of World War II

Date	July 3, 1940
Location	Plymouth, England, United Kingdom
Result	British capture of Surcouf

Belligerents

United Kingdom

France

Casualties and losses

3 killed

1 killed

Surcouf was a French cruiser submarine ordered to be built in December 1927, launched on 18 October 1929, and commissioned in May 1934. Surcouf – named after the French privateer Robert Surcouf – was the largest submarine ever built until surpassed by the first Japanese I-400-class submarine in 1943. Her short wartime career was marked with controversy and conspiracy theories. She was classified as an "undersea cruiser" by sources of her time.

The Washington Naval Treaty had placed strict limits on naval construction by the major naval powers, but submarines had been omitted. The French Navy attempted to take advantage of this by building three "corsair submarines", of which Surcouf was the only one to have been completed.

Surcouf was designed as an "underwater cruiser", intended to seek and engage in surface combat. For reconnaissance, she carried a Besson MB.411 observation floatplane in a hangar built abaft of the conning tower; for combat, she was armed with six 550 mm (22 in) and four 400 mm (16 in) torpedo tubes and twin 203 mm (8 in) guns in a pressure-tight turret forward of the conning tower. The guns were fed from a magazine holding 60 rounds and controlled by a director with a 5 m (16 ft) rangefinder, mounted high enough to view a 11 km (5.9 nmi; 6.8 mi) horizon, and able to fire within three minutes after surfacing. Using her periscopes to direct the fire of her main guns, Surcouf could increase this range to 16 km (8.6 nmi; 9.9 mi); originally an elevating platform was supposed to lift lookouts 15 m (49 ft) high, but this design was abandoned quickly due to the effect of roll. In theory, the Besson observation plane could be used to direct fire out to the guns' 24 mi (21 nmi; 39 km) maximum range. Anti-aircraft cannon and machine guns were mounted on the top of the hangar.

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Wikipedia